Final answer:
From ages 1 to 3, children experience significant brain development, achieving 55% of the adult brain size by age two and rapidly developing cognitive and motor skills. Infants develop basic social and communication abilities, and by the end of the year, may start walking. Toddlers further enhance communication and can form simple sentences and control attention and behavior.
Step-by-step explanation:
The brain development of a child between the ages of 1 and 3 is marked by rapid changes and milestones. During this period, the size of the brain increases swiftly, achieving 55% of its adult size by age 2. In these formative years, significant cognitive skills are developed. Contrary to Piaget's earlier views, recent research points out that even very young children can understand cognitive development and the properties of objects prior to direct experience with them.
Toddlers exhibit a growth in motor skills and communication abilities. By the age of 3, most children can run, climb stairs, and scribble with crayons. Language develops rapidly, with children starting to form simple sentences and becoming capable of controlling their attention and behavior, a reflection of the rapid growth in the frontal lobes associated with planning, reasoning, memory, and impulse control.
The first years of life are crucial as babies achieve important physical and cognitive milestones. For instance, they begin to smile, pay attention to others, grab toys, and start babbling. By the end of the first year, babies may even begin walking. All these developments underscore the rich cognitive and physical skills gained during the toddler stage.